Transport of Light in Tissue in Photodynamic Therapy

Profio, A. E.; Doiron, Daniel R.

doi:10.1111/j.1751-1097.1987.tb04819.x

Cited by 76 publications

(41 citation statements)

References 9 publications

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“…8 In media with dominant scattering compared to absorption, the fluence rate far from optical boundaries and the light source can be approximated using diffusion theory. 9 In more complex media, computational models are used to solve RTE under certain approximations, 10,11 including the most commonly used method-Monte Carlo simulations. 12 To estimate optical fluence in biological tissue using the above-mentioned techniques, exact knowledge of optical properties of the medium is required.…”

Section: Introductionmentioning

confidence: 99%

Mapping optical fluence variations in highly scattering media by measuring ultrasonically modulated backscattered light

et al. 2014

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Abstract. Knowledge of the local optical fluence in biological tissue is of fundamental importance for biomedical optical techniques to achieve quantification. We report a method to noninvasively measure the local optical fluence in optically inhomogeneous scattering media. The concept is based on two aspects: the local tagging of light using ultrasonic modulation and the photon path reversibility principle. Our method has advantages over known computational-based fluence mapping techniques, for its purely experimental nature and without the requirement of prior knowledge of the optical properties of the medium. We provide a theoretical formalism and validation of the method with experiments in tissue-like phantoms. Further, we combine our method with photoacoustic imaging and compensate the photoacoustic signals for fluence variations in optically inhomogeneous media. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Introductionmentioning

confidence: 99%

Mapping optical fluence variations in highly scattering media by measuring ultrasonically modulated backscattered light

et al. 2014

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“…Recently, OCT has been applied for imaging a wide range of non-transparent tissues [21][22][23]. In these tissues, a 'biological window' exists where absorption of near-infrared wavelengths is minimal and light can penetrate deep into tissue [3]. In most highly-scattering (non-transparent) tissues, imaging depths of 2-3 mm can be achieved.…”

Section: Optical Coherence Tomographymentioning

confidence: 99%

“…A 'biological window' exists in this wavelength region where attenuation is governed by scattering rather than absorption [3]. For this reason, and as an alternative to X-ray mammography that uses ionizing radiation, optical mammography is being developed.…”

Section: Introductionmentioning

confidence: 99%

Optical Coherence Tomography: Feasibility for Basic Research and Image-guided Surgery of Breast Cancer

Boppart

Luo

Marks

et al. 2004

Breast Cancer Res Treat

221

178

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SummaryDiagnostic trends in medicine are being directed toward cellular and molecular processes, where treatment regimens are more amenable for cure. Optical imaging is capable of performing cellular and molecular imaging using the short wavelengths and spectroscopic properties of light. Diffuse optical tomography is an optical imaging technique that has been pursued as an alternative to X-ray mammography. While this technique permits noninvasive optical imaging of the whole breast, to date it is incapable of resolving features at the cellular level. Optical coherence tomography (OCT) is an emerging high-resolution biomedical imaging technology that for larger and undifferentiated cells can perform cellular-level imaging at the expense of imaging depth. OCT performs optical ranging in tissue and is analogous to ultrasound except reflections of near-infrared light are detected rather than sound. In this paper, an overview of the OCT technology is provided, followed by images demonstrating the feasibility of using OCT to image cellular features indicative of breast cancer. OCT images of a well-established carcinogen-induced rat mammary tumor model were acquired. Images from this common experimental model show strong correlation with corresponding histopathology. These results illustrate the potential of OCT for a wide range of basic research studies and for intra-operative image-guidance to identify foci of tumor cells within surgical margins during the surgical treatment of breast cancer.

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“…Red/near-infrared light reaching these regions will usually have undergone multiple scattering and the optical radiance will therefore be almost isotropically distributed. The spatial distribution of the optical fluence rate can then be adequately described by the diffusion approximation of the more general equation of radiative transfer (Ishimaru 1978, Svaasand 1984, Profio and Doiron 1987. Provided that the proper boundary condition is used at the source-tissue interface, this approximation will give a good description of the fluence rate somewhat distal to the source.…”

Section: Optical Distributionmentioning

confidence: 99%

A mathematical model for light dosimetry in photodynamic destruction of human endometrium

et al. 1996

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Abstract. We are involved in the development of photodynamic therapy (PDT) as a minimally invasive method for treating dysfunctional uterine bleeding, one of the primary clinical indications for hysterectomy. In this paper, we analyse light propagation through the uterus in order to specify the requirements for a light delivery system capable of effectively performing endometrial PDT. Our approach involves developing an analytical model based on diffusion theory to predict optical fluence rate distributions when cylindrical and spherical optical applicators are placed in the uterine cavity. We apply the results of our model calculations to estimate the thermal effects of optical irradiation and the effective photodynamic optical dose. Theoretical fluence rate calculations are compared to fluence rate measurements made in fresh, surgically removed human uteri.Our results show that a trifurcated cylindrical optical applicator inserted into the human uterus can provide a light dose that is sufficient to cause photodynamic destruction of the entire endometrium. When the optical power per unit length of each cylindrical applicator is 100 mW cm −1 (at 630 nm), a fluence rate of 40 mW cm −2 is delivered to the boundary layer between the endometrium and the myometrium (a depth of about 4-6 mm). The optical fluence delivered to the boundary layer after 20 min of exposure is 50 J cm −2 , a level that is generally accepted to cause tissue damage throughout the endometrium in most patients.

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Transport of Light in Tissue in Photodynamic Therapy

Cited by 76 publications

References 9 publications

Mapping optical fluence variations in highly scattering media by measuring ultrasonically modulated backscattered light

Mapping optical fluence variations in highly scattering media by measuring ultrasonically modulated backscattered light

Optical Coherence Tomography: Feasibility for Basic Research and Image-guided Surgery of Breast Cancer

A mathematical model for light dosimetry in photodynamic destruction of human endometrium

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